Aliphatic amines produced from beef tallow, coconut oil, palm oil, and the like are important intermediates for household and industrial products. In particular, aliphatic tertiary amines are derived into a quaternary ammonium salt or the like to be used in various applications such as fabric softener, antistatic agent, and rinse base.
There are known methods for producing a tertiary amine, including a reaction of a primary or secondary amine with an alcohol in the presence of a catalyst to obtain a corresponding tertiary amine.
Such a method, however, has a problem of a decreased yield of a product due to generation of a considerable amount of side-products, in particular when a secondary amine is a starting material to produce a corresponding tertiary amine, or a mono-substituted tertiary amine by substituting a hydrogen atom attached to the nitrogen atom of the secondary amine with an alkyl group and/or an alkenyl group derived from an alcohol.
Examples of the side-product include other tertiary amines derived from a primary amine and ammonia generated by side-reactions of the starting secondary amine through reactions with the alcohol, or di-substituted tertiary amines having two alkyl and/or alkenyl groups attached to the nitrogen atom derived from the starting alcohol and tri-substituted tertiary amines having three alkyl and/or alkenyl groups attached to the nitrogen atom. In order to increase a yield of an intended tertiary amine, reduction of generation of these side-products is important.
For example, JP-A No. 61-015865 discloses a method for producing a tertiary amine using a platinum group element catalyst having a copper-nickel-Group 8 element system (referring to the Group VIII by old IUPAC, corresponding to Groups 8 to 10 by current IUPAC).
WO-A 2005/035122 discloses a method for producing a tertiary amine using an immobilized catalyst in a film form having a thickness of not more than 500 μm as a process in which complicated operations such as stirring of a slurry and separation of the catalyst from the slurry after the reaction by filtration or the like can be omitted, the slurry being generated with a powder catalyst in producing a tertiary amine.